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Russell H.
Russell H., Electronics and Mechanical Repairman
Category: Small Appliance
Satisfied Customers: 10775
Experience:  Repairing electronic devices for 20+ years, including all aspects of their workings.
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I have a Bernina Aurora QE440. Twice when I have run out of

Customer Question

I have a Bernina Aurora QE440. Twice when I have run out of bobbin thread and open the bobbin compartment, the housing falls open and the bobbin hook falls out. Now I think I have it back together but the tension is all off. The top thread on the right side of the fabric is loose with knots.
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: It happened once in February so I took the machine in for service and it came back fine. Now it just happened yesterday again.
JA: Do you plan on doing the work yourself?
Customer: I guess it depends on what needs to be done. I feel like it shouldn't need another service or repair this soon.
JA: Anything else we should know to help you best?
Customer: Don't think so.
Submitted: 8 months ago.
Category: Small Appliance
Expert:  Russell H. replied 8 months ago.

Hi, thank you for contacting My name is***** will do my best to provide the right answer to your question.

Do you have instructions as to how to put the bobbin case and bobbin hook together, and how to properly thread the machine, that you have followed? since the bobbin hook fell out.

As for the thread making knots on top of the fabric that is almost certainly owing to the thread tension being wrong.

Either the top thread is too tight (not likely if it hasn't slipped or been set differently since the bobbin hook fell out), or more likely the bobbin thread tension is wrong, probably too low.

Try adjusting tension a bit in one direction, trying a short test sew to see if knotting is less if not eliminated, and then try a bit more in that direction if it seems to be getting better.

Bobbin thread tension adjustment is usually by way of a small screw under the cover plate and near where the bobbin or the bobbin case is placed.